Problem description: Libreoffice uses only one CPU out of many when it counts ods documents, decompreessing them or in any documents which includes big table.
Steps to reproduce:
1. Create Spreadsheet
2. Fill many cells with data or formulas
3. save it, close office, and open file again
Current behavior:
it work very slowly, uses one CPU core at 100% percent, and doesn't use rest CPU cores. This behavior is in linux and windows systems.
Expected behavior:
Libreoffice will use all avalable CPU cores for counting and decompressing and that will make it more efficient.
Operating System: Ubuntu
Version: 4.0.3.3 release

PC - at home
Windows 7 x64 Home premium
Celeron E3300 2.5 GHz 2 cores
3GB ram
PC- at work (there is over 150, I can sit and work on any of it but the one I use mostly)
Windows 7 x64 Professional
Core i3 2.6 GHz 4 cores
4gb Ram
Laptop
Ubuntu 12.04 x64 and Windows 7 x64 Home Premium
AMD APU E-450 1.6 GHz 2 cores
4Gb ram
(Interesting that on laptop in Ubuntu LibreOffice, also using one core, works faster even though the laptop is slower than my PCs)

(In reply to comment #0)
> Problem description: Libreoffice uses only one CPU out of many when it
> counts ods documents, decompreessing them or in any documents which includes
> big table.
>
> Steps to reproduce:
> 1. Create Spreadsheet
> 2. Fill many cells with data or formulas
> 3. save it, close office, and open file again
>
> Current behavior:
> it work very slowly, uses one CPU core at 100% percent, and doesn't use rest
> CPU cores. This behavior is in linux and windows systems.
>
> Expected behavior:
> Libreoffice will use all avalable CPU cores for counting and decompressing
> and that will make it more efficient.
Sounds like an enhancement request.
Severity -> Enhancement

All documents of some pages with images in writer are displayed very slowly when browsing.
Better display accelerating is welcome and multithreading would help greatly.
Firefox is a good example of rapid displaying code for long pages with images. Perhaps is it reusable or it give ideas ?

Intel Core Quad CPU Q6600 @2.40GHz
8GB Ram
Win 10 pro x64
Trouble with Draw that slow down cause only one core is working at 100%. De document is freezing for a minor changement.
I use many different type of fonts and some 3D spheres

Calc experiences slow downs with charts
To recreate:
- open Calc and create small data set: rows: 0 to 2 in 0.001 steps (approximately 2000 rows); 5 columns, all start at 0, but have different increments
- select all data points from data set
- create chart: Chart Type=XY (Scatter) -- Points and Lines -- [Finish]
- GUI of LibreOffice considerably slows down after creation of graph
If chart is out of view, GUI is very fast again.
In LibreOffice 4.4.4.3 (distributed with Fedora 22) moving view to different rows is:
- slow, if complete chart is in view
- slow, if chart is partly visible
- fast, if chart is not in view
At least with version 5.1.x drawing speed has improved for me.
In LibreOffice 5.1.5.2 (distributed with Fedora 24) and in LibreOffice 5.2.0.4 (tested with Flatpak on Fedora 24) moving view to different rows is:
- fast, if complete chart is in view
- slow, if chart is partly visible
- fast, if chart is not in view
It seems the whole chart is redrawn, if part of it is visible. Then again if more is visible.
This results in slow work with those charts.
Maybe the chart can be used from memory all time and only be redrawn, if its data has been changed?
On the same machine (Intel Core 2 Duo E8500 @ 3.16GHz; 4 GB RAM; GeForce 9500 GS) Microsoft Office 2010 32 bit on Windows 7 32 bit is fast in all 3 cases.
LibreOffice on Windows on the same machine shows the behaviour described above.

Resource usage in LO is still a problem and I think it should be taken as an important task.
I promote the usage of LO for all document generation in the enterprise I work, but performance is a recurrent problem.
By implementing a serious multithreading system into LO and a better resource usage policy the LO reception in corporation environment would be better IMHO.

Hello,
Is it possible to add Multi-Threading?
At least 1 thread per document.
So when opening, editing or running macro in large document, this don't block all other opened?
Or add an argument to run multi process.

One place I would very much like to see multithreading is PDF export. When exporting a 100 slide Impress presentation to PDF it takes about 5 minutes. It would be a lot quicker if it scaled with multi-core/thread CPUs.

I have the same problem,
- Problem description: Libreoffice uses only one CPU out of many when convert, concat, insert fields in odt documents, I use Unoruntime
- Installation:
Libreoffice 4.4
Java version "1.7.0_91" OpenJDK Runtime Environment (IcedTea 2.6.2) (suse-21.2-x86_64) OpenJDK 64-Bit Server VM (build 24.91-b01, mixed mode)
SUSE Linux Enterprise Server 12 SP1 (x86_64)
- Current behavior: (same as the first comment)
it work very slowly, uses one CPU core at 100% percent, and doesn't use rest CPU cores. This behavior is in linux and windows systems.
- Expected behavior: (same as the first comment)
Libreoffice will use all avalable CPU cores for counting and decompressing and that will make it more efficient.

(In reply to Agustín from comment #15)
This bug is already confirmed, so do not change the status back to UNCONFIRNED.
Also, Muilti-Threading is already a work-in-process and is available on master branch for Calc. It was disabled on 6.0 branch at this moment because of bugs, but I expect this feature be enabled soon in releases.